mdw@git.distorted.org.uk Git - userv-utils/blob - ipif/mech-blowfish.c

   1 /*
   2  * Blowfish
   3  *
   4  * arguments: key size in bits (must be multiple of 8)
   5  *
   6  * key values: 8 byte random IV and n byte random key
   7  *
   8  * encoding:         do CBC encryption overwriting message
   9  * encoding for MAC: do CBC and prepend last ciphertext block
  10  */
  11
  12 #include "forwarder.h"
  13 #include "blowfish.h"
  14
  15 struct mechdata {
  16   unsigned char iv[BLOWFISH_BLOCKBYTES];
  17   struct blowfish_cbc_state cbc;
  18 };
  19
  20 static void mds_blowfish(struct mechdata **md_r) {
  21   struct mechdata *md;
  22   unsigned long keysize;
  23   unsigned char key[BLOWFISH_MAXKEYBYTES];
  24
  25   XMALLOC(md);
  26
  27   keysize= getarg_ulong();
  28   arg_assert(!(keysize & 7));
  29   keysize >>= 3;
  30   arg_assert(keysize > 0 && keysize <= BLOWFISH_MAXKEYBYTES);
  31
  32   random_key(md->iv,sizeof(md->iv));
  33   random_key(key,keysize);
  34
  35   blowfish_loadkey(&md->cbc.ek, key,keysize);
  36   *md_r= md;
  37 }
  38
  39 static void mes_blowfish(struct mechdata **md_r, int *maxprefix_io, int *maxsuffix_io) {
  40   mds_blowfish(md_r);
  41 }
  42
  43 static void mds_bfmac(struct mechdata **md_r) {
  44   mds_blowfish(md_r);
  45 }
  46
  47 static void mes_bfmac(struct mechdata **md_r, int *maxprefix_io, int *maxsuffix_io) {
  48   mds_blowfish(md_r);
  49   *maxprefix_io += BLOWFISH_BLOCKBYTES;
  50 }
  51
  52 #define MSGSIZE_OUT                                                   \
  53   msgsize= buf->size;                                                 \
  54   arg_assert(!(msgsize & (BLOWFISH_BLOCKBYTES-1)));
  55
  56 #define MSGSIZE_IN                                                    \
  57   msgsize= buf->size;                                                 \
  58   if (msgsize & (BLOWFISH_BLOCKBYTES-1)) return "not multiple of block size"
  59
  60 #define FOREACH_BLOCK(func,inptr,outptr)                              \
  61  {                                                                    \
  62    unsigned char *ptr;                                                \
  63    blowfish_cbc_setiv(&md->cbc, md->iv);                              \
  64    for (ptr= buf->start;                                              \
  65         ptr < buf->start + msgsize;                                   \
  66         ptr += BLOWFISH_BLOCKBYTES) {                                 \
  67      func(&md->cbc,inptr,outptr);                                     \
  68    }                                                                  \
  69  }
  70
  71 static void menc_blowfish(struct mechdata *md, struct buffer *buf) {
  72   unsigned long msgsize;
  73   MSGSIZE_OUT;
  74   FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,ptr);
  75 }
  76
  77 static const char *mdec_blowfish(struct mechdata *md, struct buffer *buf) {
  78   unsigned long msgsize;
  79   MSGSIZE_IN;
  80   FOREACH_BLOCK(blowfish_cbc_decrypt,ptr,ptr);
  81   return 0;
  82 }
  83
  84 static void menc_bfmac(struct mechdata *md, struct buffer *buf) {
  85   unsigned long msgsize;
  86   unsigned char outblock[BLOWFISH_BLOCKBYTES];
  87
  88   MSGSIZE_OUT;
  89   FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,outblock);
  90   memcpy(buf_prepend(buf,BLOWFISH_BLOCKBYTES), outblock, BLOWFISH_BLOCKBYTES);
  91 }
  92
  93 static const char *mdec_bfmac(struct mechdata *md, struct buffer *buf) {
  94   unsigned long msgsize;
  95   unsigned char outblock[BLOWFISH_BLOCKBYTES];
  96   unsigned char *checkblock;
  97
  98   BUF_UNPREPEND(checkblock,buf,BLOWFISH_BLOCKBYTES);
  99   MSGSIZE_IN;
 100   FOREACH_BLOCK(blowfish_cbc_encrypt,ptr,outblock);
 101   if (memcmp(checkblock,outblock,BLOWFISH_BLOCKBYTES)) return "verify failed";
 102   return 0;
 103 }
 104
 105 const struct mechanism mechlist_blowfish[]= {
 106   STANDARD_MECHANISM("blowfish-cbcmac", bfmac)
 107   STANDARD_MECHANISM("blowfish-cbc",    blowfish)
 108   { 0 }
 109 };